Automatic focusing camera

ABSTRACT

An automatic focusing camera comprises a measuring device formed integrally with a camera housing, defining a distance measuring zone selectively extended in different directions, and adapted for producing information employed for focusing to an object contained in the extended distance measuring zone. A position detecting device for detecting the position of the camera housing, and a device for varying the extending direction of the distance measuring zone, in response to the position of the camera housing detected by the position detecting device.

.Iadd.CROSS-REFERENCE TO RELATED APPLICATIONS.Iaddend.

.[.This.]. .Iadd.This reissue application is a continuation ofapplication Ser. No. 780,129 filed Dec. 26, 1996, abandoned, which is acontinuation of application Ser. No. 576,167 filed Dec. 19, 1995,abandoned, which is a continuation of application Ser. No. 299,346 filedSep. 1, 1994, abandoned, for reissue of U.S. Pat. No. 5,144,358 grantedSep. 1, 1992, which matured from application Ser. No. 603,246 filed Oct.24, 1990, which .Iaddend.is a continuation of application Ser. No.317,742 filed Mar. 1, 1989, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automatic focusing camera whichcontrols focusing by producing plural information for focus adjustmentfrom the object field.

2. Related Background Art

In conventional automatic focusing cameras, the information for focusadjustment (distance measuring information or defocus information) isproduced by projecting light from a light-emitting unit to an objectpositioned in the center of the object field determined by the viewfinder and receiving the light reflected from said object, but, therecannot be obtained information for focus adjustment, in case ofphotographing with an image frame composition with the main object notpositioned in the center, thus resulting in a so-called central defocuspicture.

In order to prevent failure in the control resulting from such centraldefocus, there is already realized a so-called multi-focus camera inwhich plural light-emitting elements are provided for producinginformation for focus adjustment in plural positions in the objectfield, and also the present applicant proposed a similar camera in theU.S. application Ser. No. 204,905 dated Jun. 10, 1988, now U.S. Pat. No.4,908,646, issued Mar. 13, 1990.

However, such camera designed to produce plural information for focusadjustment from the object field may still result in such centraldefocus if the position of the camera is moved, since the plurallight-emitting elements are arranged on the assumption that the positionof the camera is constant at the photographing operation.

For example, when plural light-emitting elements are arranged in ahorizontal row in the usual photographing position of the camera, if thecamera is turned by 90° so that said plural light-emitting elements arearranged vertically at the center of the object field and if mainobjects are positioned at left and right in said object field, therecannot be obtained the focus adjusting information for such objects andthere is again encountered the central defocus phenomenon.

In order to prevent such central defocus phenomenon resulting fromchange in the camera position, it has been proposed to distribute alarge number of light-emitting elements over a relatively wide areaincluding the center of the object field.

However, the use of such many light-emitting elements requires complexprocessing for selecting the information finally used in focusingcontrol from many focus adjusting information from said light-emittingelements, thus resulting in an elevated cost due to a complex circuitstructure if said processing is achieved by hardware, or a longer timerequired for such selection if said processing is achieved by software.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an automatic focusingcamera capable of reliably preventing such central defocus phenomenonwith simple structure and processing, even when the camera position ischanged.

The above-mentioned object can be achieved, according to the presentinvention, by an automatic focusing camera provided with a distancemeasuring zone selectively extending in different directions and capableof producing information on the distance to an object contained in theextended distance measuring zone, comprising position detecting meansfor detecting the camera position and means for varying the extendingdirection of said distance measuring zone according to the positiondetected by said position detecting means.

Said distance measuring zone is so varied as to always assume ahorizontal row or an upward or downward V-shape regardless of the cameraposition.

In such automatic focusing camera of the present invention, certainmeasuring points are selected to prevent the central defocus phenomenonaccording to the change in the camera position, so that appropriateautomatic focusing can be achieved without such phenomenon, regardlessof the camera position.

Also the number of the measuring points is maintained at a minimumnecessary value, whereby the discrimination process for focusing controlcan be simplified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B, 1C and 1D are schematic views showing light-emittingpatterns corresponding to camera positions in a first embodiment;

FIG. 2 is a block diagram of a light emission control circuit;

FIG. 3 is a block diagram of a variation of the light emission controlcircuit;

FIG. 4 is a flow chart showing the function of the circuit shown in FIG.3;

FIGS. 5A, 5B, 5C and 5D are schematic views showing light-emittingpatterns corresponding to camera positions in a second embodiment;

FIG. 6 is a block diagram of a light emission control circuit;

FIG. 7 is a block diagram of a variation of the light emission controlcircuit;

FIG. 8 is a flow chart showing the function of the circuit shown in FIG.7;

FIG. 9 is a schematic view showing the arrangement of a light emittingunit and a light receiving unit on a camera, with light emissionpatterns of the first embodiment;

FIG. 10 is a schematic view showing a light receiving position on a PSD;

FIG. 11 is a schematic view showing the arrangement of a light emittingunit and a light receiving unit on a camera, with light emissionpatterns of the second embodiment;

FIG. 12 is a schematic view showing a variation of the arrangement ofthe light emitting unit and the light receiving unit on the camera, withlight emission patterns of the first embodiment;

FIGS. 13A, 13B, 13C and 13D are schematic views showing arrangements oflight-receiving elements corresponding to the camera positions in athird embodiment;

FIG. 14 is a block diagram of a selection-control circuit; and

FIG. 15 is a flowchart showing the function of the circuit shown in FIG.14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, there will be described certain embodiments applied toan active camera, provided with a light-emitting unit for emittinginfrared light beams to form light spots on an object, and a lightreceiving unit for receiving the reflected light from the object, andcapable of producing information for focus adjustment based on theprinciple of triangulation.

FIGS. 1A to 1D illustrate an embodiment of the arrangement of plurallight-emitting elements in the light-emitting unit, and light-emittingpatterns corresponding to various camera positions.

In the light-emitting unit at the front part of the camera there areprovided, corresponding to light target positions schematically shown ina viewing field of the finder represented by a broken-line frame, alight-emitting element I5 at the center and other light-emittingelements I1, I2, I3 and I4 positioned vertically and horizontallythereto. These drawings indicate the arrangement of the light-emittingelements I1 to I4, provided in the light-emitting unit in the front partof the camera, seen from the back. Also provided are two mercuryswitches HS1, HS2, as the position detecting means for detecting thecamera position, to the left of the viewing field of the finder in whichthe elements I1-I5 are illustrated. Said mercury switches HS1, HS2 arepositioned in an inverted-V arrangement in the normal camera position Ishown in FIG. 1A, and are both turned off in the position in FIG. 1A, asthe mercury is separated from paired leads.

Corresponding to different camera positions I, II, III and IV, thelight-emitting pattern of the light-emitting unit with five elementsI1-I5 in a cross-shaped arrangement is selectively controlled asrespectively indicated by the dark circles.

It is to be noted that, though the camera is shown in differentpositions I-IV at left, the arrangement of the light-emitting elementsin the viewing field and the position of the mercury switches HS1, HS2are fixedly shown in the state of position I, and that, in each of thepositions II-IV, the upper position is indicated by an arrow.

In these positions I-IV, the light-emitting pattern and the function ofthe mercury switches HS1, HS2 vary in the following manner.

In the normal photographing position I, the elements I3, I5 and I4 inthe horizontal row selectively emit light. In this state the mercuryswitches HS1, HS2 are both turned off.

In the position II in which the right side of the viewing field ispositioned upwards, the clement I1, I5 and I2 in the horizontal row inthis position selectively emit light. The mercury switch HS1 is turnedoff, while the mercury switch HS2 is turned on.

In the position III in which the left side of the viewing field ispositioned upwards, the elements I1, I5 and I2 in the horizontal row,the same as those in the position II, selectively emit light. In thisposition, the mercury switches HS1, HS2 are respectively turned on andoff.

Finally, in the inverted camera position IV, in which the lower side ofthe viewing field is positioned upwards, the elements I3, I5 and I4arranged in the horizontal row as in the position I selectively emitlight. The mercury switches HS1, HS2 are both turned on in this state.

Thus, with the cross-shaped arrangement of five light-emitting elementsI1-I5, a light-emission pattern is produced with three light-emittingelements arranged in the horizontal row, in any of the positions I-IV.

The on-off operations of the mercury switches HS1, HS2 in the positionsI-IV are summarized in Tab. 1.

                  TABLE 1                                                         ______________________________________                                        POSITION          HS1    HS2                                                  ______________________________________                                        I                 OFF    OFF                                                  II                OFF    ON                                                   III               ON     OFF                                                  IV                ON     ON                                                   ______________________________________                                    

FIG. 2 is a block diagram of an embodiment of hardware for selectivelycontrolling the light-emitting elements I1-I5 shown in FIG. 1 accordingto the detection outputs of the camera position.

The mercury switches HS1, HS2 are connected to a power source Vccrespectively through pull-up resistors, and the outputs of said switchesat the side of said pull-up resistors are supplied to an exclusive ORgate 1. Consequently, when the mercury switches HS1, HS2 are both on oroff, namely in case of the position I or IV, said exclusive OR gate 1provides an L-level signal, and, when either of said switches is offwhile the other is on, namely in case of the position II or III, theexclusive OR gate 1 provides an H-level signal. In each of the camerapositions I-IV, a driver 7 drives a light-emitting element positioned atthe left side of the horizontal row, while a driver 8 drives the elementI5 at the center, and a driver 9 drives, at each of the positions I-IV,a light-emitting element positioned at the right side of the horizontalrow.

NAND gates 3, 5 receive the output of the driver 7, and NAND gates 4, 6receive the output of the driver 9. Also the output of the exclusive ORgate 1 is supplied to the NAND gates 5, 6 and, through an inverter 2, tothe NAND gates 3, 4. The output of the driver 8 is supplied directly tothe light-emitting element I5 at the center. Other light-emittingelements I1-I4, positioned in cross arrangement, respectively receivethe outputs of the NAND gates 3-6.

In the following there will be explained the function of the embodimentshown in FIG. 2, with reference to the camera positions I-IV and thelight emission patterns corresponding to said camera positions.

Firstly, in the position I shown in FIG. 1A, the mercury switches HS1,HS2 are both turned off as shown in Tab. 1, whereby the exclusive ORgate 1 receives H-level input signals to release an L-level outputsignal. Consequently the NAND gates 5, 6 are disabled, while the NANDgates 3, 4, receiving an H-level signal through the inverter 2, areenabled. When H-level drive signals are released from the drivers 7, 9in such state, the NAND gates 3, 4 receiving H-level signals releaseL-level signal to activate the light-emitting elements I3, I4. At thesame time the central light-emitting element I5 is activated by the-output of the driver 8, whereby there is obtained a light-emissionpattern by the elements I3, I5, I4 arranged in the horizontal row. Thelight emission control in the position IV is the same as that in theposition I explained above. More specifically, in the position IV, themercury switches HS1, HS2 are both turned on as shown in Tab. 1, wherebythe exclusive OR gate 1 receives L-level input signals to generate anL-level output signal. Thus the light-emitting elements I3, I5, I4 areactivated in the same manner.

In the position II shown in FIG. 1B, the mercury switches HS1, HS2 arerespectively turned off and on as shown in Tab. 1. Thus the exclusive ORgate 1 receives an H-level input signal and an L-level input signal togenerate an H-level output signal, whereby the NAND gates 3, 4 receivingthe inverted output signal through the inverter 2 are disabled while theNAND gates 5, 6 receiving the output of the exclusive OR gate 1 areenabled. Thus the NAND gates 5, 6 receiving the H-level drive signalsfrom the drivers 7, 9 generate L-level output signals, therebyactivating the light-emitting elements I1, I2. At the same time thecentral light-emitting element I5 is activated directly by the output ofthe driver 8.

Also in the position III shown in FIG. 1C, the mercury switches HS1, HS2are respectively turned on and off as shown in Tab. 1 whereby theexclusive OR gate 1 generates an H-level output signal as in the case ofthe position II. Thus the NAND gates 5, 6 are enabled to drive thelight-emitting elements I1, I2, and simultaneously the central elementI5 is activated.

FIG. 3 is a block diagram of another embodiment in which thecross-shaped pattern shown in FIG. 1 is selectively activated bysoftware, and FIG. 4 is a flow chart corresponding to said software.

A CPU 10 for executing a program according to the flow chart shown inFIG. 4 receives the switch output signals from the mercury switches HS1,HS2 connected to the power source Vcc through the pull-up resistors, andoutput ports P1-P5 of said CPU 10 are respectively connected to thelight-emitting elements I1-I5 of the light-emitting unit.

In the following there will be explained the control of thelight-emitting pattern according to the camera position in thisembodiment shown in FIG. 3, while making reference to the flow chartshown in FIG. 4.

In the position I in which the mercury switches HS1, HS2 are both turnedoff, at first a step S1 discriminates the off-state of the mercuryswitch HS1, then a step S2 discriminates the off-state of the mercuryswitch HS2 whereby the sequence proceeds to a step S3 to select theoutput ports P3, P4 of the CPU 10, and a step S4 then selects the outputport P5. In this manner the light-emitting elements I3, I5, I4 areactivated. On the other hand, in the position IV in which the mercuryswitches HS1, HS2 are both turned on, the step S1 discriminates theon-state of the mercury switch HS1 whereby the sequence proceeds to astep S5 which discriminates the on-state of the mercury switch HS2. Thusthe sequence proceeds to the step 3 to select the output ports P3 and P4as in the case of position I, and then the step S4 selects the outputport P5. In this manner the elements I3, I5 and I4 are activated.

In the position II in which the mercury switches HS1, HS2 arerespectively off and on, the step S1 discriminates the off-state of themercury switch HS1, and then the step S2 discriminates the on-state ofthe mercury switch HS2 whereby the sequence proceeds to a step S6 toselect the output ports P1 and P2 of the CPU 10. Then the step S4selects the output port P5, so that the light-emitting elements I1, I5,I2 are activated.

In the position III, in which the mercury switches HS1, HS2 arerespectively on and off, the step S1 discriminates the on-state of theswitch HS1 whereby the sequence proceeds to the step S5 whichdiscriminates the off-state of the switch HS2. Thus the sequenceproceeds to the step S6 to select the output ports P1, P2 as in the caseof the position II, and then the step S4 selects the output port S5,whereby the light-emitting elements I1, I5 and I2 are activated.

In the embodiments shown in FIGS. 2 and 3, the three light-emittingelements selected according to the camera position are preferablyactivated in succession rather than simultaneously.

FIG. 5 shows another embodiment of the arrangement of plurallight-emitting elements provided in the light-emitting unit.

As in FIG. 1, the arrangement of the plural light-emitting elements isschematically shown in the viewing field of the finder, and thelight-emitting patterns corresponding to the camera positions I-IV arerepresented by dark circles. The elements I1-I4 are shown in a stat seenfrom the back of the camera. Also there are shown function states of themercury switches HS1, HS2 as in FIGS. 1A to 1D.

In the present embodiment, a light-emitting element I15 is positioned atthe center of the viewing field of the finder, and four otherlight-emitting elements I11, I12, I13, I14 are respectively positionedin the diagonal directions of said viewing field.

In the present embodiment, corresponding to each of the camera positionsI-IV, three out of five light-emitting elements are selectivelyactivated so as to form an inverted V-shape in the upward directionindicated by an arrow. As the central element I15 is always activated inany of the positions I-IV, two other elements are selectively activatedaccording to the camera position.

FIG. 6 is a block diagram of an embodiment of hardware for selectivelycontrolling the light-emitting unit of the diagonal pattern shown inFIG. 5, according to the detected camera position.

The mercury switches HS1, HS2 and the drivers 7, 8, 9 are same as thoseshown in FIG. 2, but there are provided inverters 21, 22, and the NANDgates 3-6 are connected in a different manner to the light-emittingelements I11-I15.

More specifically, the output of the mercury switch HS1 is directlysupplied to an input terminal of the NAND gate 5, and, through theinverter 21, to an input terminal of the NAND gate 3. Also the output ofthe mercury switch HS2 is directly supplied to an input terminal of theNAND gate 6, and, through the inverter 22, to an input terminal of theNAND gate 4. The other input terminals of the NAND gates 3, 5 areconnected to the output of the driver 7, while those of the NAND gates4, 6 are connected to the output of the driver 9. The outputs of theNAND gates, 3, 4, 5, 6 are respectively supplied to the light-emittingelements I11, I12, I13, I14. The output of the driver 8 is directlysupplied to the central light-emitting element I15.

In the following there will be explained the function of the embodimentshown in FIG. 6, with reference to FIG. 5.

At first, in a position I shown in FIG. 5A, in which the mercuryswitches HS1, HS2 are both turned off as shown in Tab. 1, said switchesgenerate H-level signals whereby the NAND gates 3, 4 receiving L-levelsignals from the inverters 21, 22 are disabled, while the NAND gates 5,6receiving the H-level signals directly from said switches ar enabled. Inresponse to the H-level output signals from the drivers 7, 9, the NANDgates, 5, 6 generate L-level outputs to activate the light-emittingelements I13, I14. At the same time the central element I15 is activatedby the output of the driver 8, thereby forming a light emission patternof inverted V-shape. In a position IV shown in FIG. 5D in which themercury switches HS1, HS2 are both turned on, said switches generateL-level signals, whereby the NAND gates, 3, 4 receiving the invertedH-level signals from the inverters 21, 22 are enabled. Thus, in responseto the H-level output signals of the drivers 7, 9 the elements I11, I12are activated. At the same time the central element I15 is activateddirectly by the output of the driver 8. In this manner, in the positionIV, thee is obtained a light emission pattern of inverted V-shape withthe light-emitting elements I11, I15 and I12.

In a position II shown in FIG. 5B in which the mercury switches HS1, HS2are respectively off and on, the NAND gate 5 is enabled by the H-leveloutput signal of the mercury switch HS1, and the NAND gate 4 is enabledby the H-level signal from the inverter 22, whereby the light-emittingelements I12, I13 and I15 are activated to form a light emission patternof inverted V-shape.

In a position III shown in FIG. 5C, in which the mercury switches HS1,HS2 are respectively on and off, the NAND gate 3 is enabled by theH-level signal from the inverter 21 and the NAND gate 6 is enabled bythe H-level signal from the switch HS2, whereby the light-emittingelements I11, I14 and the central element I15 are activated to obtain alight emission pattern of inverted

FIG. 7 is a block diagram of another embodiment in which fivelight-emitting elements arranged in a diagonal pattern shown in FIG. 5are selectively controlled by software, and FIG. 8 is a flow chartcorresponding to said software.

A CPU 10 receives the output signals of the mercury switches HS1, HS2,and output ports P11-P15 of said CPU 10 are respectively connected tothe five light-emitting elements I11-I15.

At first, in the position I in which the mercury switches HS1, HS2 areboth turned off, a step S11 discriminates the off-state of the switchHS1, and, then a step S12 selects the output port P13 to activate thelight-emitting element I13. Then a step S13 discriminates the off-stateof the switch HS2, and a step S14 selects the output port P14 toactivate the light-emitting element I14. Subsequently a step S15 selectsthe output port P15 to activate the element I15. Thus, in the positionI, there is obtained a light emission pattern of inverted V-shape by thelight-emitting elements I13, I15 and I14.

In the position II in which the mercury switches HS1, HS2 arerespectively off and on, at first the step S11 discriminates theoff-state of the switch HS1, and the step S12 selects the output portP13 to activate the light-emitting element I13. Then the step S13discriminates the on-state of the switch HS2 whereupon the sequenceproceeds to a step S17 for selecting the output port P12 therebyactivating the light-emitting element I12. Then the step S15 selects theoutput port S15 to activate the central element I15. Consequently, alsoin the position II, there is obtained a light emission pattern ofinverted V-shape by the light-emitting elements I12, I15 and I13.

In the position III in which the mercury switches HS1, HS2 arerespectively on and off, at first the step S11 discriminates theon-state of the switch HS1, whereby the sequence proceeds to a step S16for selecting the output port P11 thereby activating the element I11.Then the step S13 discriminates the off-state of the switch HS2, wherebythe sequence proceeds to a step S14 for selecting the output port P14thereby activating the element I14. Then the step S15 activates thecentral element I15. Therefore, also in the position III, there can beobtained a light emission pattern of inverted V-shape by thelight-emitting elements I11, I15 and I14.

In the position IV, in which the mercury switches HS1, HS2 are bothturned on, the sequence proceeds from the step S11 to S16 to activatethe element I11, then from the step S13 to S17 to activate the elementI12, and the step S15 activates the element I15. Thus, in the positionIV, a light emission pattern of inverted V-shape is obtained with thelight-emitting element I11, I15 and I12.

FIG. 9 shows an embodiment, in which a light-emitting unit 32 on thecamera body is provided with five light-emitting elements I1-I5 arrangedin a cross-shaped pattern shown in FIG. 1, and a light-receiving unit 34with a predetermined distance to said light-emitting unit, at the sidethereof. The light beams emitted from the light-emitting elements I1-I5of the light-emitting unit 32 to an object of a given distance arereceived at positions R1-R5 on the light-receiving unit 34. Stateddifferently, the light-receiving positions R1-R5 on the light receivingunit 34 are mutually displaced, corresponding to the pattern of thelight-emitting element I1-I5 in the light-emitting unit 32.

The light-receiving unit 34 is composed of a position sensing device(PSD) of the lateral direction. Consequently the light-receivingpositions R1, R2, positioned above and below the central light-receivingposition R5, do not generate errors in the detection signals as they arein a same position in the distance axis (lateral direction), but thelight-receiving positions R3, R4 will result in errors in theinformation for focus adjustment, because they are displaced from thecentral light-receiving position R5 in the distance axis.

Therefore, in the embodiment shown in FIG. 9, the signals are correctedas shown in Tab. 2, respectively corresponding to the camera positionsI-IV.

                  TABLE 2                                                         ______________________________________                                        Camera position                                                                            Correction                                                       ______________________________________                                        I            Ad1 for the position R4                                                       Ad2 for the position R3                                          II           None                                                             III          None                                                             IV           Ad1 for the position R4                                                       Ad2 for the position R3                                          ______________________________________                                    

It is assumed that the light-receiving positions R3, R4 are respectivelydistanced by d1, d2 from the central light-receiving position R5 in thelateral direction or direction of the distance axis on thelight-receiving unit 34, and Ad1 and Ad2 are corresponding correctionvalues.

When the same distance is measured with light-projecting andlight-receiving lenses of the same focal length in the structure shownin FIG. 9, there is obtained a relation:

d1=d1'

wherein d1' is the distance between the light-emitting elements I5 andI4. Stated differently the distance between the light spots on the PSDis equal to that of the light-emitting elements. As shown in FIG. 10,the length of the PSD in the direction of the distance axis isrepresented by L, and the length from an electrode A to the position R4or R5 is respectively represented by Xa or Xb. It is to be noted that,when a light spot is formed in any of the positions R1-R5, the lightspot should not be present at other positions. When the light spot isformed at R5, the distance information is given by the followingequation, based on output photocurrents IA, IB from the electrodes A, B:##EQU1##

Also the distance information when the light spot is formed at R4 isrepresented by: ##EQU2## Despite the fact that the measured distance issame, these two distance information mutually differ by a followingamount D: ##EQU3## Therefore, when the light spot is formed at R4, thedistance information is to be obtained by adding _(L) ² d1 to the outputphotocurrent of the PSD.

In the following there will be explained the correction for each cameraposition, with correction values Ad=_(L) ² d1 and Ad2=-_(L) ² d2.

At first, in the position II or III, the light-emitting elements I1, I5and I2 in the vertical row of the light-emitting unit 32 are activatedas shown in FIG. 1, and the light spots are formed at R1, R5 and R2 inthe light-receiving unit 34. The detection signals are not corrected inthis case, because said light spots are not displaced in the directionof the distance axis.

On the other hand, in the position I or IV, the light-emitting elementsI3, I5 and I4 in the horizontal row of the light-emitting unit 32 areactivated, and the light spots are formed at R3, R5 and R4 displaced inthe direction of the distance axis of the light-receiving unit 34, thusgenerating errors. Consequently, in the camera position I or IV, thecorrection value Ad2 is applied to the detection signal corresponding tothe position R3, and the correction value Ad1 is applied to thedetection signal corresponding to the position R4.

FIG. 11 shows an embodiment of the camera with a light-emitting unit ofthe diagonal pattern shown in FIG. 5. Also in such light-emitting unitof the diagonal pattern, the light beams emitted from the light-emittingelements I11-I15 to an object of a given distance are received atpositions R11-R15 in a light-receiving unit 44, wherein the positionsR11, R14 positioned to the left of the central position R15 generateerrors corresponding to a positional aberration of d11, while thepositions R12, R13 to the right of the position R14 generate errorscorresponding to d12.

Consequently the detection signals are corrected as shown in Tab. 3,corresponding to the camera positions I-IV.

                  TABLE 3                                                         ______________________________________                                        Camera position                                                                            Correction                                                       ______________________________________                                        I            Ad1 for position R14                                                          Ad2 for position R13                                             II           Ad2 for position R12                                                          Ad2 for position R13                                             III          Ad1 for position R11                                                          Ad1 for position R14                                             IV           Ad2 for position R12                                                          Ad1 for position R11                                             ______________________________________                                    

More specifically, in the position I in which the light-emittingelements I13, I15 and I14 are activated, the detection signals areobtained at the light-receiving positions R13, R15 and R14. Thuscorrections Ad1 and Ad2 are made respectively for the positions R14 andR13. In the position II in which the light-emitting elements I12, I15and I13 are activated, the detection signals are obtained at thelight-receiving positions R12, R15 and R13. Thus a correction Ad2 isapplied to said positions R12, R13. Also in the camera position III inwhich the light-emitting elements I11, I15 and I14 are activated, thedetection signals are obtained at the light-receiving positions R11, R15and R14. Thus a correction Ad1 is applied to the positions R11 and R14.Finally, at the camera position IV in which the light-emitting elementsI11, I15 and I12 are activated, the detection signals are obtained atthe light-receiving positions R11, R15 and R12, and corrections Ad1 andAd2 are applied respectively at the position R11 and R12.

FIG. 12 shows another embodiment provided with a light-emitting unit 32the same as in FIG. 9 but not requiring the correction on the detectionsignals. Corresponding to said light-emitting unit 32, there areprovided a vertical light-receiving unit 51 and a horizontallight-receiving unit 53, either one of which is selected according tothe camera position.

More specifically, when three light-emitting elements I3, I5 and I4 inthe horizontal row in the light-emitting unit 32 are activated for theobject of a given distance, the reflected light spots are formed atpositions R3, R5, R4 likewise in a horizontal row on the light-receivingunit 51. In such case, therefore, said light-receiving unit 51 isselected, as there is involved no positional aberration in thelongitudinal direction, or direction of the distance axis, of said unit51. On the other hand, when the light-emitting elements I1, I5 and I2 inthe vertical row in the light-emitting unit 32 are activated, thelight-receiving unit 53 is selected since the light-receiving positionsR1, R5 and R2 are not aberrated in the direction of the distance axis ofsaid light-receiving unit 53.

In this manner the light-receiving unit 51 is selected for the cameraposition I or IV, and the light-receiving unit 53 is selected for thecamera position II or III, and such selection of the light-receivingunit dispenses with the correction of the detection signalscorresponding to the change in the light emission pattern depending onthe camera position.

In the above-explained light emission control of the light-emitting unitwith a diagonal pattern, there are always selected two light-emittingelements in addition to the central element so as to always form a lightemission pattern of inverted V-shape according to the camera position,but it is also possible to form a light emission pattern of V-shape withrespect to the camera position.

In the following there will be explained a third embodiment applied topassive automatic focusing, employing TTL phase difference detectionwith a CCD line sensor or the like in a single-lens reflex camera oremploying optical triangulation as disclosed in U.S. Pat. No. 4,002,899.FIGS. 13A to 13D indicate the functions of distance measuring zones andmercury switches HS1, HS2 in the camera positions I-IV. In the viewingfield of the finder, indicated by a broken-line frame, there are shownperpendicularly crossing two distance measuring zones I21, I22.

In the usual camera position I, a CCD sensor array corresponding to thedistance measuring zone I21 is automatically selected, and an algorithmof data transfer and correlation calculation is executed. In this statethe mercury switches HS1, HS2 are both turned off.

In the camera position II, a CCD sensor array corresponding to thedistance measuring zone I22 is automatically selected, and an algorithmof data transfer and correlation calculation is executed. In this state,as the right side of the viewing field is positioned upwards, themercury switches HS1, HS2 are respectively turned off and on.

In the camera position III, the CCD sensor array corresponding to thedistance measuring zone I22 is automatically selected as in the case ofthe position II. In this state, as the left side of the viewing field ispositioned upwards, the mercury switches HS1, HS2 are respectivelyturned on and off.

In the inverted camera position IV, the CCD sensor array correspondingto the distance measuring zone I21 is selected as in the case of theposition I. In this state, as the lower side of the viewing field ispositioned upwards, the mercury switches HS1, HS2 are both turned on.

In this manner, in any of the positions I to IV, there is selected adistance measuring zone which appears horizontally in the viewing field.

The on-off operations of said switches HS1, HS2 in different camerapositions are the same as shown in Tab. 1.

FIG. 14 is a block diagram of the circuit of the third embodiment, inwhich a pair of distance measuring zones is selectively controlledaccording to the detected camera position.

The mercury switches HS1, HS2 are connected to a power source Vccthrough pull-up resistors, and are connected, at the side of saidpull-up resistors, to a CPU 60. Said CPU 60 is connected through asignal output line 61 and a signal input line 62 to a motor drivecircuit 64, which is further connected to a focusing motor 65 and aphotointerruptor 66 for detecting the lens motion caused by saidfocusing motor 65. The CPU 60 is further connected, through a signaloutput line 67 and a signal input line 68, to a CCD drive circuit 69,which is connected with light-receiving elements 71, 73, 75, 77respectively through signal lines 72, 74, 76, 78.

In case of a single-lens reflex camera, the light-receiving face of thelight-receiving unit 70 is in a position conjugate for example with theexit pupil of a photographing lens, and receives a light fluxtransmitted by said photographing lens.

The light-receiving elements 71, 73, 75, 77 are respectively composed oflinear CCD sensors, and are positioned radially, around the center ofthe light-receiving unit 70, thus receiving light flux portions comingfrom the object, through respectively different areas of the exit pupil.

On the other hand, in the distance measuring method disclosed in theU.S. Pat. No. 4,002,899 mentioned above, the light-receiving unit 70 isplaced in a position for receiving the light flux coming from theobject, through a window provided in the front face of the camerahousing.

In the following the function of the circuit shown in FIG. 14 will beexplained with reference to a flow chart shown in FIG. 15.

The distance measuring operation is started by the closing of a mainpower switch, or by the actuation of a shutter release button over afirst stroke.

A step S21 starts charge accumulation in the four light-receivingelements, and a step S22 terminates said charge accumulating operationafter a predetermined time, or after an appropriate time determined bythe CPU so as to obtained an appropriate amount of accumulated charge.Then the sequence proceeds to a step S23.

In the position I shown in FIG. 13A, in which the mercury switches HS1,HS2 are both turned off, the step S23 provides an affirmativediscrimination, whereby the sequence proceeds to a step S24 forselecting the input/output lines 74, 78 of the CCD drive circuit 69, andthen to a step S26. Also in the camera position IV in which the mercuryswitches HS1, HS2 are both turned on, the step S23 again provides anaffirmative discrimination, whereby the sequence proceeds to the stepS24 to select the lines 74, 78 as in the case of the position I, andthen to the step S26.

In the camera position II or III, the step S23 provides a negativeresult, whereby the sequence proceeds to a step S25 to select the lines72, 76 of the CCD drive circuit, and then to the step S26.

Thus, in the camera position I or IV, the CPU selects the ports 74, 78of the CCD drive circuit 69 through the output line 67 of the CPU, andthen proceeds to the step S26 to read, in succession the accumulatedcharges of the light-receiving element 73 through the line 74 and theinput line 68 of the CPU, to send these values to an A/D converter inthe CPU and to store the converted values in an internal memory of theCPU. Then it reads the accumulated charges of the element 77, insuccession, through the line 78 and the input line 68, and stores theconverted digital values in said internal memory. Then, in a step S27,it determines the amount of defocus by correlation calculation on thestored data of the light-receiving elements 73, 77.

On the other hand, in the camera position II or III, the CPU selects theports 72, 76, and similarly determines the amount of defocus in thesteps S26 and S27.

Then the CPU sends the information on the amount of movement of thefocusing lens, determined from the amount of defocus, to the motor drivecircuit 64 through the port 61, thus driving the focusing motor 65. Whenthe amount of rotation of said motor, detected by the photointerruptor66, reaches a predetermined value corresponding to said amount ofdefocus, the CPU stops the motor, thereby completing an automaticfocusing cycle. In this manner the data transfer time required fortransferring the data from the CCD line sensors to the CPU can bereduced to a half, in comparison with the case of data transfer from allthe distance measuring areas. Also the distance measuring operation canbe achieved faster, since the distance measuring area is reduced tohalf, so that the time required for correlation calculation is alsohalved.

I claim:
 1. An automatic focusing camera comprising:a camera housing; distance measurement means including light emitting means formed integrally with said camera housing and provided with plural light emitting elements for respectively emitting radiation beams toward mutually different portions of an object field; position detecting means for detecting a position of said camera housing; and control means for selectively driving a part of said plural light emitting elements for the emission of said radiation beams, that varies in response to the position of said camera housing detected by said position detecting means.
 2. An automatic focusing camera according to claim 1, wherein said light emitting means comprises plural elements for respectively emitting said radiation beams toward portions of said object field positioned substantially radially about a center of said object field, and said control means is adapted to select said part of the light emitting elements in such a manner that portions of said object field illuminated by the radiation beams emitted by the selected part of the light emitting elements have a substantially constant pattern with respect to direction and shape, regardless of change in the position of said camera housing.
 3. An automatic focusing camera according to claim 2, wherein the radiation beams emitted from the part, selected by said control means, of the light emitting elements form spots arranged substantially in a horizontal line in said object field.
 4. An automatic focusing camera according to claim 2, wherein the radiation beams emitted from the part, selected by said control means, of the light emitting elements form spots arranged in a V-shaped pattern in said object field.
 5. An automatic focusing camera according to claim 1, wherein said light emitting means comprises a reference element for emitting a radiation beam toward a central portion of said object field, and other plural elements for respectively emitting plural radiation beams toward portions positioned around said central portion, and said control means is adapted to select said part of the light emitting elements in such a manner that portions of said object field illuminated by the radiation beams emitted by the selected part of the light emitting elements have a substantially constant pattern shape, regardless of a change in the position of said camera housing.
 6. An automatic focusing camera according to claim 1, further comprising light receiving means formed integrally with said camera housing and adapted to receive the radiation beams reflected in said object field.
 7. An automatic focusing camera according to claim 6, wherein said light receiving means comprises a light receiving face on which said reflected radiation beams are incident and is adapted to generate an output corresponding responding to an incident position on said light receiving face.
 8. An automatic focusing camera according to claim 7, wherein said light receiving means comprises means for correcting the output of said light receiving means according to an arrangement of said light emitting elements, and said correcting means is adapted to determine the correction of said output, according to the detected position of said camera housing.
 9. An automatic focusing camera according to claim 1, wherein said control means comprises a plurality of drive circuit means for driving said light emitting elements and means for actuating said drive circuit means selectively to drive different groups of said plural light emitting elements depending upon a position of said camera housing detected by said position detecting means, said groups corresponding to different distance measuring zones, respectively, of said object field.
 10. An automatic focusing camera according to claim 1, wherein said plural light emitting elements consist solely of five light emitting elements including a central light emitting element, disposed at a center of a rectangle, at corners of which four light emitting elements are disposed, respectively, and wherein said control means drives said central light emitting element and together therewith drives different pairs of said four light emitting elements depending on the position of said camera housing detected by said position detecting means.
 11. An automatic focusing camera according to claim 10, wherein one pair of said four light emitting elements and said central element are disposed along a first line and another pair of said four light emitting elements and said central element are disposed along a second line orthogonal to said first line.
 12. An automatic focusing camera according to claim 10, wherein said different pairs of light emitting elements form with said central element different triangular arrangements.
 13. An automatic focusing camera comprising:a camera housing; distance measurement means including light emitting means formed integrally with said camera housing and provided with plural light emitting elements for respectively emitting radiation beams toward mutually different portions of an object field; position detecting means for detecting a position of said camera housing; control means for selectively driving a part of said plural light emitting elements for the emission of said radiation beams, that varies in response to the position of said camera housing detected by said position detecting means; light receiving means formed integrally with said camera housing for receiving radiation beams reflected in said object field, said light receiving means comprising a light receiving face on which said reflected radiation beams are incident and generating an output corresponding to an incident position of beams on said light receiving face, said light receiving face being spaced laterally from said light emitting means along a distance axis; and means for correcting the output of said light receiving means in accordance with the incident position of a reflected radiation beam on said light receiving face and according to the detected position of said camera housing.
 14. An automatic focusing camera according to claim 13, wherein said light receiving means comprises a plurality of light receiving elements adjacent to said light receiving face, at least one of said light receiving elements being spaced a different distance from said light emitting means than another of said light receiving elements along said distance axis, and wherein said correcting means corrects the output of said light receiving means to compensate for said different distance.
 15. An automatic focusing camera according to claim 13, wherein said light emitting elements are arranged to define a first pair of orthogonal lines, and said light receiving elements are arranged to define a second pair of orthogonal lines, one of the lines of each pair being parallel to said distance axis and the other lines of each pair being perpendicular to said distance axis.
 16. An automatic focusing camera comprising:a camera housing: distance measurement means including right emitting means formed integrally with said camera housing and provided with plural light emitting elements for respectively emitting radiation beams toward mutually different portions of an object field; position detecting means for detecting a position of said camera housing; control means for selectively driving a part of said plural light emitting elements for the emission of said radiation beams, that varies in response to the position of said camera housing detected by said position detecting means; and light receiving means formed integrally with said camera housing for receiving radiation beams reflected in said object field, said light receiving means comprising groups of light receiving elements arranged to define a pair of orthogonal lines, one of said lines being spaced laterally from said light emitting means in a first direction parallel to a distance axis and being perpendicular to said axis, the other of said lines being spaced laterally from said light emitting means in a second direction perpendicular to said first direction and being parallel to said distance axis.
 17. An automatic focusing camera comprising:a camera housing; distance measurement means including light emitting mean son said camera housing including plural light emitting elements adapted to be driven for emitting respective radiation beams toward mutually different portions of an object field, said plural light emitting elements comprising a reference element for emitting a radiation beam toward a substantially central portion of the object field and other elements for emitting respective radiation beams toward portions around said central portion; position detecting means for detecting a position of said camera housing; and control means for selectively driving a part of said plural light emitting elements that varies depending on the position of said camera housing detected by said position detecting means, said control means selectively driving said light emitting elements in such a manner that said reference element is included in the selectively driven part of said plural light emitting elements regardless of the position of said camera housing.
 18. An automatic focusing camera according to claim 17, wherein the radiation beams emitted from the part of the light emitting elements selectively driven by said control means form spots arranged in a V-shaped pattern in said object field.
 19. An automatic focusing camera according to claim 18, which further comprises light receiving means on said camera housing for receiving radiation beams reflected in the object field and generating a position signal indicative of the position of a radiation beam incident on said light receiving means.
 20. An automatic focus adjusting camera comprising:a camera housing; light emitting means on said camera housing including plural light emitting elements adapted to be driven for emitting respective radiation beams toward mutually different portions of an object field; control means for selectively driving a part of said plural light emitting elements; light receiving means on said camera housing for receiving radiation beams reflected in the object field, said light receiving means comprising a light receiving face on which said reflected radiation beams are incident, said light receiving face being extended in a predetermined direction and spaced laterally from said light emitting means along said predetermined direction, said light receiving means generating an output which indicates the position, along said predetermined direction of a radiation beam incident on said light receiving face; and means for adjusting the output of said light receiving means depending on the part of said plural light emitting elements driven by said control means and for producing focus adjustment information.
 21. An automatic focus adjusting camera according to claim 20, which further comprises position detecting means for detecting a position of said camera housing and outputting a detection signal, wherein said control means selectively drives a part of said plural light emitting elements determined by said detection signal.
 22. An automatic focus adjusting camera comprising:a camera housing: light emitting means on said camera housing including plural light emitting elements adapted to be driven for emitting respective radiation beams toward mutually different portions of an object field; control means for selectively driving a part of said plural light emitting elements; two light receiving means on said camera housing for receiving radiation beams reflected in the object field, each of said two light receiving means having a light receiving face which is extended in a different direction from the light receiving face of the other light receiving means and generating an output indicative of the position, along the respective extended direction, of a radiation beam incident on the light receiving face thereof; and means for selectively an output of one of said two light receiving means when said control means drives a predetermined part of said plural light emitting elements and for selecting an output of the other of said two light receiving means when said control means drives another predetermined part of said plural light emitting elements.
 23. An automatic focusing camera according to claim 22, which further comprises position detecting means for detecting a position of said camera housing and outputting a detection signal, wherein said control means selectively drives a part of said plural light emitting elements determined by said detection signal. .Iadd.
 24. A camera comprising:a light receiving device disposed on an opposite side of a photographing lens from an object field to receive light through the photographing lens from first and second areas on the object field and generate a plurality of light intensity distribution signals corresponding to said first and said second areas, said light receiving device having a first sensor corresponding to said first area and a second sensor corresponding to said second area, said first area being extended in a horizontal direction and said second area being extended in a vertical direction when said camera is held in a horizontal attitude; a focus condition detecting circuit electrically connected to said light receiving device to detect a focus condition of said photographing lens in response to the output signals of said light receiving device; and an attitude detecting device which detects that said camera is held in a vertical attitude to produce a vertical attitude signal, said focus condition detecting device not being responsive to said first sensor and being responsive to said second sensor when said vertical attitude signal is produced..Iaddend..Iadd.25. A camera according to claim 24, wherein said attitude detecting device detects that said camera is held in the horizontal attitude to produce a horizontal attitude signal, and wherein said focus condition detecting device is responsive to said first sensor when said horizontal attitude signal is produced..Iaddend..Iadd.26. A camera comprising:a light receiving device disposed on an opposite side of a photographing lens from an object field to receive light through the photographing lens from the object field, said light receiving device having a first sensor and a second sensor, said first sensor being extended in a horizontal direction and said second sensor being extended in a vertical direction when said camera is held in a horizontal attitude, said sensors generating light intensity distribution output signals; a focus condition detecting circuit electrically connected to said light receiving device to detect a focus condition of said photographing lens in response to output signals of said sensors; and an attitude detecting device which detects that said camera is held in a vertical attitude to produce a vertical attitude signal, said focus condition detecting device being unresponsive to output signals from said first sensor and being responsive to output signals from said second sensor when said vertical attitude signal is produced..Iaddend..Iadd.27. A camera according to claim 26, wherein said attitude detecting device detects that said camera is held in the horizontal attitude to produce a horizontal attitude signal, and wherein said focus condition detecting device is responsive to output signals from said first sensor and is unresponsive to output signals from said second sensor when said horizontal attitude signal is produced..Iaddend. 